Chinese yam polysaccharide promotes jejunal development, antioxidant defense, and mucosal immunity in weaned rats

Introduction Chinese yam polysaccharide (CYP), a heteropolysaccharide composed of mannose, xylose, arabinose, glucose, and galactose, has been reported to exhibit immunomodulatory and antioxidant properties. However, its role in regulating intestinal development and mucosal barrier function remains incompletely understood. This study investigated the effects of dietary CYP supplementation on antioxidant status, jejunal morphology, digestive function, and mucosal immunity in weaned rats. Methods Thirty specific-pathogen-free male Sprague–Dawley rats (initial body weight: 50.16 ± 0.50 g) were randomly assigned to three dietary groups (n = 10 per group) for a 28-day feeding trial: a control group fed a basal diet and two treatment groups fed the basal diet supplemented with 0.1% or 0.5% CYP. At the end of the experiment, blood and jejunal tissues were collected for biochemical, histomorphological, and molecular analyses. Results Compared with the control group, supplementation with 0.5% CYP significantly reduced plasma malondialdehyde (MDA) concentrations ( P < 0.05) and increased total antioxidant capacity ( P < 0.01), which was associated with activation of the MAPK ERK1/2–Nrf2 signaling pathway. Both 0.1% and 0.5% CYP supplementation significantly increased jejunal villus height and the villus height-to-crypt depth ratio ( P < 0.05), while reducing intraepithelial lymphocyte numbers ( P < 0.05). Moreover, rats receiving 0.5% CYP exhibited significantly higher activities of lactase, sucrase, and maltase, along with increased jejunal immunoglobulin A (IgA) and β-defensin levels ( P < 0.05 or P < 0.01). Additionally, CYP supplementation at both inclusion levels markedly upregulated the expression of Claudin-1 and Mucin-1 ( P < 0.01). Discussion Collectively, these findings demonstrate that dietary CYP enhances systemic antioxidant defense, promotes jejunal structural development, and strengthens intestinal mucosal barrier function in weaned rats.